We will study polyfunctional catalysis as a basis for the catalytic activity and selectivity of enzymes. The reactions studied will be largely those of carbonyl compounds, such as a-hydrogen exchange, aldol condensation, carbinolamine and iminium ion formation, ester and amide hydrolysis and formation, and rearrangement of glyoxal derivatives. The catalysts will usually be amines, especially diamines, and will often be cyclic compounds so as to have relatively rigid structures. We will start with relatively simple compounds and study their mechanisms of catalysis in detail so as to be able to understand the mechanism of action of more complicated compounds that more closely approximate natural enzymes. Since the action of polyfunctional catalysts, including most enzymes, ordinarily involves cyclic transition states, we will carry out molecular mechanics calculations to help in estimating the stabilities of such transition states. We plan to study the stereoselectivity of polyfunctional catalysts as well as th ability of such catalysts to discriminate between non-stereoisomers.